He demonstrated last October that he can walk the tightrope of the postseason without falling. Now he must prove that he can negotiate the long, bumpy road of the regular season, which forces even the best relievers to trip and puts pebbles in their shoes.

The Giants approach their World Series title defense with Romo as their primary closer. But he's likely not their sole closer. Manager Bruce Bochy has indicated that Romo, who has a history of elbow problems, will receive occasional breaks from late-inning duty to preserve his valuable right arm.

"I don't know if he's proved if he can handle a week where he throws four or five times in seven days," Giants general manager Brian Sabean said.

Romo cares about his job, which is a wonderful quality in any human being. But Major League closers are best equipped to survive the occasional yet inevitable blown saves when they learn to shrug off their failures as quickly as possible. Because they might face the same situation the next day.

"I think that's going to be an adjustment for him, dealing with the ups and downs of being a closer," Bochy said. "With his makeup and personality, he does take it hard. He feels like he's letting all his teammates down. ... If something does happen that is not good, you have to put it behind you."

Putting the World Series behind them, or at least preserving it in the proper perspective, is a significant Spring Training objective for the Giants. But flashbacks couldn't be helped on Tuesday as Romo threw his first session of live batting practice. Suddenly, Scottsdale Stadium became Comerica Park, and memories awakened of that wintry Oct. 28 in Detroit, when Romo slipped an 89-mph fastball past an immobile Miguel Cabrera to seal the Giants' four-game Series sweep.

"I think that was going through a few minds," Bochy said.

The man himself avoided such reveries.

"I've had a lot of times this offseason to reflect on what happened," Romo said. "Today was just pretty much [a matter of] trying to stay focused and be in the zone."

Romo has spent virtually his entire career in the zone. Relying mostly on his slider, the right-hander has accumulated career statistics which seem almost fictional. They include a 5.77 strikeout-to-walk ratio, averages of 1.9 walks and 10.7 strikeouts per nine innings and a 0.88 WHIP (walks and hits per inning). Romo doesn't beat himself, which makes him an ideal candidate to preserve late-inning leads.

The Giants realized this last season, after Tommy John surgery sidelined Brian Wilson and Bochy removed Santiago Casilla from the closer's role. Romo converted 14 of 15 save opportunities while evolving into the bullpen's big man down the stretch. He added four saves while allowing one earned run in 10 2/3 innings spanning 10 postseason appearances. Romo's three World Series saves equaled the number of big league saves he had accumulated entering the 2012 season, reflecting the dizzying change in his responsibilities.

To handle the transition from being a setup reliever, Romo sought advice from Wilson, whose 163 saves from 2008-11 were the most in the Majors, and Robb Nen, the Giants' all-time leader with 206 saves.

Romo distilled their counsel into simple logic.

"It came down to -- get your outs and then celebrate, regardless of the situation," he said. "Regardless of what's at stake, you gotta get your outs. Get your job done and then you can go be happy, then you can show everyone the excitement of what we accomplished."

As summer turned to fall, the Giants' belief in Romo deepened. Romo, who turns 30 on March 4, acknowledged that he fed off that feeling.

"I trusted my teammates, their faith and confidence in me, the most," he said. "It never wavered. It kind of made me feel like it was, 'Get it to Romo, and then it's over.' That made me feel like a million bucks every time I got the ball. If I lacked any confidence or faith in myself, I wouldn't have been able to do that. But then again, once I got a chance to fully trust them, I think it made me that much better."

The same drive to excel leaves Romo crestfallen when he blows a lead.

"I don't like to be the guy [teammates] cannot count on," Romo said. "It's just that conscious effort, that conscious fight within myself to be the best I can. I take offense to a guy getting a base hit off me. I take offense to a guy getting comfortable in the box against me. Why? Why not? The guy's trying to take food off my table. I'm a hungry individual. ... It's like I'm in a fistfight when I pitch. It's my best against your best. When it comes to being hard on myself, I'm honest with myself as well. I do expect a lot out of myself. I wouldn't be here, I feel, if I didn't think that way or have that approach."

Chris Haft is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.